Rotary engine compensating eccentric



Jwiy 1970 w. KALKBRENNER 3,520,644

ROTARY ENGINE COMPENSATING ECCENTRIC Filed June 27, 1968 IN VEN TOR.

RALPH W. KALKBRENNER Fig. 2

United States Patent US. Cl. 418-57 2 Claims ABSTRACT OF THE DISCLOSURE An eccentric for a rotary piston steam engine employing a spring operated biasing construction for maintaining the outer surface of said eccentric in contact with the wall of the cylinder as the surfaces wear.

BACKGROUND OF THE INVENTION Recent studies indicate that an artificial human heart supported by an implantable power source is technically feasible; that is, a modest extension of proven technology, without the necessity of engineering breakthroughs, is all that is required to produce the working parts of such a system.

One implantable system which has been proposed, and appears to offer a genuine prospect of success, is a system which utilizes a steam cycle with an isotopic source of heat, a steam engine driven water pump, and a replacement blood pump which is energized by the water under pressure.

A system of this type, of course, can only be successfully employed if the operative elements are miniaturized, reliable, and capable of long life. One element of the system which has received considerable attention is that of a steam engine of rotary piston design.

The rotary piston steam engine is known to be a highly reliable device which is capable of great miniaturization. However, an important drawback of this engine as presently available arises from the fact that the rotating solid eccentric must be built to close dimensional tolerances and must maintain good contact with the wall of the cylinder for satisfactory efiiciency and reliability. In time, as a result of wear and changing load conditions, this good contact in the conventional solid eccentric is gradually lost and along with it the efiiciency and power it had initially.

SUMMARY OF THE INVENTION The invention described herein was made in the course of, under a contract with the US. Atomic Energy Commission.

The present invention avoids or minimizes the aforementioned disadvantages associated with the use of the solid eccentric rotor in a rotary piston engine by providing a rotor construction in which good contact is made initially with less stringent dimensional tolerance control and this contact is maintained during the life of the engine.

In accordance with the principles of this invention, the eccentric rotor assembly consists of a rotor shaft on which is mounted the eccentric which is provided with a leaf spring to maintain required roller to cylinder wall contact.

It is thus a principal object of this invention to provide an eccentric rotor for use in a rotary piston engine having reduced dimensional tolerance requirements and capable of greater life at maximum efficiency.

Other objects and advantages of this invention will hereinafter become more apparent from the following 3,520,644 Patented July 14, 1970 ice description of a preferred embodiment of this invention taken with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 illustrates a view in section of a rotary cylinder incorporating the principles of this invention;

FIG. 2 is a view along 22 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the figures there is shown steam engine 10 consisting of a cylinder wall 12 forming a circular cylinder A through which passes engine shaft 14 supporting eccentric rotor assembly 15. As is understood in the art, engine 10 is provided with steam inlet and outlet plenums 16 and 18 with inlet and outlet ports 22 and 24, respectively, and a curtain valve 26 biased (i.e. by a spring, not shown) to ride on the surface of eccentric rotor 15 to separate inlet from outlet flow. Curtain valve 26 has a wheel 27 which makes contact with the outer surface of eccentric rotor 15.

Eccentric rotor assembly 15 which rotates clockwise as understood in the art consists of a cylindrical eccentric core 28 supported on and pinned to shaft 14 by a dowel 32. Core 28 is cylindrical on one side as shown and is provided with shoulders 32a and 32/1 with a smaller diameter cylindrical section 34. Surrounding eccentric core 28 is a ring 46 containing a semicircular leaf spring 38 connected at the center thereof by a lock button 42 to ring 36. By this construction it is seen that ring 36 is biased in the direction shown by arrow B. Surrounding ring 36 are a bushing 44 and a roller 46 which contact the inner surface of cylinder wall 12 at point C.

When eccentric roller assembly 15 is initially assembled roller 46 contacts wall 12 at point C and a small space exists between eccentric core 28 and ring 36 at D. It will be seen that as wall 12 and roller 46 wear during use, leaf spring 38 will maintain these elements in good contact as the space at D gradually reduces in size. It is also evident that manufacture of these elements does not require the degree of precision which would be required if the biasing arrangement described did not exist.

During operation of the apparatus described, the parts will stay in intimate contact during the useful life of engine 10 without decreases in efficiency which normally would occur as the parts wear. In addition, greater reliability is attained because of the reduced possibility of breakdown due to poor contact.

It is thus seen that there has been provided an improved eccentric for a rotary piston engine. While only a preferred embodiment of the invention has been described, it is understood that many variations thereof are possible without departing from the principles of this invention and that the invention is, therefore, to be defined by the scope of the appended claims.

I claim:

1. In a rotary piston engine employing an engine shaft within a circular cylinder the improvement comprising:

(a) a circular roller of smaller outside diameter than the inside diameter of said cylinder surrounding said engine shaft mounted for rotation with said shaft, said roller having a continuous outer surface;

(b) means for biasing said roller ececntrically about said shaft to maintain eccentric contact of said continuous outer surface with the inner wall of said cylinder during rotation of said shaft, said biasing means consisting of a semi-circular leaf spring mounted within said roller and core means eccentrically mounted on said shaft for supporting said leaf spring; and

(c) means supporting said biasing means for permitting said contact to continue as said roller and 3 4 cylinder wear at contacting surfaces during opera- 517,985 4/1894 Smith 91-103 tion of said engine. 724,224 3/1903 Weichmann 91-103 X 2. The engine of claim 1 in which said core means in- 775,413 11/1904 Behringer 91103 X cludes a pair of shoulders for supporting the ends of 1,653,748 12/1927 Van Hamersveld et a1. said leaf spring. 5 91-103 X References Cited EVERETTE A POWELL JR P Ex mn rlma UNITED STATES PATENTS ry a 1 er 83,766 11/1868 Currie 9l103 X 404,557 6/1889 Phelps 91103 

